Interpretation of positron-annihilation data with respect to the electron-positron enhancement factors. II. Applications.

Abstract

The theoretical considerations of the properties of positron-annihilation characteristics in simple metals, presented in the previous paper, are verified for the alkali metals and Mg. Results are based on a local-density approach to electron-positron correlations and band-structure calculations are performed within the linear-muffin-tin-orbitals--average-spheres approximation. The validity of the average electron density approximation is discussed and the effective densities, determined by electron-positron correlation effects, are presented for valence electrons in simple metals. Methods of extracting the full shape of the electron-positron momentum density from experimental curves are recommended. The proposed analysis of experimental data applied to simple metals allows more reliable verificaton of the shape of electron-positron enhancement factors near the Fermi surface.